Hydraulic controls for an earthmoving blade or the like



G. E. GRANT A ril 3, 1962 HYDRAULIC CONTROLS FOR AN EARTHMOVING BLADE ORTHE LIKE Filed Oct. 12, 1959 2 Sheets-Sheet 1 lllllll V "1 INVENTOR.65mm E GRANT ATTORNEYS April 3, 1962 G. E. GRANT HYDRAULIC CONTROLS FORAN EARTHMOVING BLADE OR THE LIKE Filed Oct. 12, 1959 I. v II mm: mm 1 2Sheets-Sheet 2 ELE -3...

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GEE/4L0 E. Glen/VT ATTORNEYS" 3 027,722 HYDRAULIC CQNTRO LS FGR ANEARTHMOVING BLADE OR THE LIKE Gerald E. Grant, East Peoria, 111.,assignor to Caterpillar Tractor (10., Peoria, Ill., a corporation ofCalifornia Filed st. 12, 1959, Ser. No. 845,933 2 Claims. (til. 6t -97)This invention relates to hydraulic control means and particularly tomeans employed for efiectiug operation of either one of two hydraulicmotors separately or of both motors in unison.

The invention is applicable to the control of various types of apparatusbut is particularly useful for the control of the earthmoving blade of amotor grader or the like and is, therefore, described herein inconnection with such use, as an example, for the purpose of illustratingthe manner in which it functions.

A motor grader blade is ordinarily supported for vertical movementrelative to the machine upon which it is mounted to adjust the depth ofout which it makes. It is also supported for vertical movement of eitherof its ends relative to the other to enable tilting of its cutting edgefor forming banks, ditch walls or other sloping surfaces. Thisordinarily requires at least two controls, there being one for each endof the blade and it being necessary, therefore, to actuate both controlssimultaneously to raise or lower the blade without tilting it orchanging its angular setting. This makes it impossible for the operatorto adjust other controls manually or even to steer the machine while theblade is being adjusted giving rise to difficult and sometimes dangerousoperating conditions.

It is the object of the present invention to provide an improved controlsystem for motor grader blades or other devices which may be actuated byhydraulic motors and wherein it is necessary to operate selectivelyeither one or both motors. Another object of the invention is to providecontrol means for actuating either one or both of a pair of hydraulicmotors by a single lever to enable an operator simultaneously to operateother controls.

Further and more specific objects and advantages of the invention residein the construction and arrangement of its various components and willbecome apparent upon an understanding of the following specificationwherein reference is made to the accompanying drawings.

In the drawings:

FIG. 1 is a schematic view of a control system embodying the presentinvention, and showing the relationship in a circuit of two controlvalves with the hydraulic adjusting mechanism of an earthmoving blade;

FIG. 2 is a schematic view of one of the valves shown in FIG. 1illustrating another position of adjustment thereof; and

FIG. 3 is a similar view of the same valve adjusted to a third position.

The system illustrated in FIG. 1 includes a hydraulic pump 8 fordirecting fluid under pressure through either one of two manuallyoperated valves generally indicated at 10 and 11 for actuating eitherone or both of a pair of hydraulic motors herein illustrated as doubleacting hydraulic jacks 12 and 14 which adjustably support a blade 15 ofa motor grader or the like, the jacks being pivotally suspended from themain frame of the machine, a portion of which is illustrated at 9.

The control valves 10 and 11 are identical in construction and eachcomprises, as illustrated in the valve 10, a valve spool 16 reciprocablymounted in the bore 18 of a valve body 20. Fluid under pressure from thepump may be introduced to the bore of the valve through a conduit 21, aninlet passage 22 and either of a pair of passages 24 and 26 whichcommunicate between the inite States Patent 0 3,027,722 Patented Apr. 3,1962 let passage 22 and the bore. A pair of spring loaded check valves28 and 30 normally close passages 32 and 34 to permit flow of fluidunder pressure from the pump to the jacks through circuits which areopened upon manipulation of the valve spool in a manner presently to bedescribed and to prevent reverse flow in the event of failure of thepump to operate. Two ports 36 and 38 communicating with the bore of thevalve form communication with the head ends of the jacks 12 and 14,respectively, through a pair of conduits 44 and 46. Similar ports 40 and42 form communication with the rod ends of the jacks 12 and 14 throughconduits 48 and 50. A plurality of ports 52, 54, 56, and 58 whichcommunicate with the bore of the valve body are connected by a commonpassage with an outlet port 60 which communicates with the inlet passage22a of the valve 11, which corresponds to the inlet 22 in the valve 10,through a conduit shown at 62.

The reference characters employed on the valve 10 are used foridentification of identical parts in the valve 11 but followed by thecharacter (a) and the valve 11 is connected in the same manner as thevalve 10 with the jacks 12 and 14 through the ports 36a, 38a, 40a and42a through conduits 46a, 44a, 50a and 48a, respectively, correspondingto the similarly numbered conduits which lead to the jacks 12 and 14from the valve 10. The drain port 60a of the valve 11 connects with aconduit 62a which returns to the sump or supply tank indicated at 64from which the pump 8 withdraws the operating fluid.

Each of valves 10 and 11 employs a centering spring assembly generallyindicated at 70 of conventional construction, the function of which isto hold the valve spool in a centered position which is the positionillustrated in FIG. 1. One or more spring loaded detents, two of whichare illustrated at 72 in FIG. 1, are urged into engagement with thesides of the spool for cooperation with circumscribing grooves 74therein to indicate to an operator when the spool has attained certainpositions and also to retain the spool in predetermined positions ofadjustment. The spools are adjustable as by a pair of operators controllevers illustrated at 66 and 66a.

In order to actuate the jack 12 to raise the left end of the blade 15 asviewed in FIG. 1, the spool 16 of the valve Ill is adjusted to theposition of FIG. 2 until the detents 72 enter one of the grooves 74,this being the lower groove as viewed. In this position, fluid underpressure from the pump is directed to the rod end of the jack 12 by wayof the conduit 21, port 26 and through check valve 30 and passage 34 andthe valve bore to the port 40 and conduit 48 which communicates with thejack 12.

Both of the jacks 12 and 14 may be retracted simultaneously to raise theblade 15 without tilting it or changing its angular position, whateverit may be, by actuation of the same valve to move its spool beyond theposition of FIG. 2 and to that shown in FIG. 3 wherein the output of thepump is delivered through the valve bore and to both of the outlets 40and 42 for communication with both of the rod ends 12 and 14. This isthe extreme movement of the valve spool to the position where it islimited by the solid height of the spring in the centering assembly 70.

As the lands on opposite ends of the valve spool are bi-symmetric insize and spacing from the central portion thereof, and the outlet ports36 and 38 are bi-symmetrically disposed with respect to the outlets 4t]and 42, it is apparent that operation of the control lever 66 in theopposite direction will effect direction of fluid under pressure toeither one or both jacks 12 and 14 to extend them and lower the blade15, either at one end, upon partial movement of the control lever, or atboth ends, upon full movement thereof. Thus the valve may be actuated toraise or lower one end of the blade or to raise or lower both endssimultaneously. Since the valves are identical in construction, it isapparent from the foregoing description that the valve 11 may beactuated to raise or lower the opposite end of the blade 15 as Well asto raise or lower the entire blade. It is possible, therefore, byoperation of only one control lever at a time, to obtain any desiredadjustment of the blade which is possible through actuation of the jacksl2 and 14.

If the machine is at rest, or if for any other reason it is safe for theoperator to employ both hands, more rapid adjustment of the blade can beaccomplished by simultaneously operating both of the control valves 10and 11. For example if the valve spool 16 and 16a are moved in oppositedirections to their blade tilting positions, one jack will be advancedwhile the other is retracted and a rapid adjustment of the tilt angle isaccomplished. The full output of the pump may also be employed forvertical adjustment of the blade as for example to raise it quickly bymoving both valve spools to the position shown in FIG. 2. In thisposition, the fluid from the pump 3 is directed to the rod end of jack12 in the manner previously described and the return flow from the headend of the jack 12 passes through conduit 44 and ports 36 into the valvebore and thence through passage 54 into conduit 62 and to inlet port 22aof valve 11 which is positioned to communicate pressure to the rod endof jack 14 through passage 40a and conduit 50a. In this manner, bothjacks are retracted simultaneously and rapidly because the full outputof fluid under pressure from the pump is utilized.

I claim:

1. For combination with a vehicle having an operated element such as anearthmoving blade and means supporting said element including a doubleacting hydraulic jack adjacent each end thereof, and means to supplyfluid pressure to said jacks comprising a valve in the fluid circuit; acontrol member on said valve movable in one direction to first supplyfluid to a first of said jacks to raise one end of the operated elementand upon further movement to supply fluid to both jacks simultaneouslyto raise the entire element, said same control member being movable inthe opposite direction to first supply fluid to the opposite end of saidfirst jack to lower one end of the operated element and upon furthermovement to the opposite end of both jacks simultaneously to lower theentire element, and a second similar valve and control member operablelike the first to effect independent op eration of the second of saidjacks and simultaneous operation of both jacks, and means directingreturn flow from one jack operated by one valve through the other valvewhereby the entire output of fluid under pressure is available to raiseor lower said operated element upon actuation of both control members.

2. For combination with a vehicle having an operated element such as anearthmoving blade and means supporting said element including a doubleacting hydraulic jack adjacent each end thereof, and means to supplyfluid pressure to said jacks comprising a valve in the fluid circuit; acontrol member on said valve movable in one direction to first supplyfluid to a first of said jacks to raise one end of the operated elementand upon further movement to supply fluid to both jacks simultaneouslyto raise the entire element, said same control member being movable inthe opposite direction to first supply fluid to the opposite end of saidfirst jack to lower one end of the operated element and upon furthermovement to the opposite end of both jacks simultaneously to lower theentire element, and a second similar valve and control member operablelike the first to eflect independent operation of the second of saidjacks and simultaneous operation of both jacks, said valves beingconnected in series in the fluid circuit to enable their simultaneousoperation to raise one end of the operated element and lower the otherend thereof.

References Cited in the file of this patent UNITED STATES PATENTS446,799 Thorpe Feb. 17, 1891 1,538,167 Chappell et a1. May 19, 19252,077,674 Coyle Apr. 20, 1937 2,232,357 Argo Feb. 18, 1941 2,370,526Doran Feb. 27, 1945 2,636,290 Bell Apr. 28, 1953 2,800,847 Bennett July30, 1957

